Monolithic ceramic waveguide filter with wide spurious free bandwidth

This paper presents two new design techniques for improving the spurious performance of an integrated ceramic waveguide filter without compromising its figure-of-merit e.g. Q-factor. Non-uniform width ceramic waveguide resonators are used to spread the undesired higher order mode frequencies along with ceramic TEM resonators reducing the overall cutoff frequency of the resonators. The proposed designs offer 60-65% better spurious performance in comparison with uniform width integrated ceramic waveguide filter. Simulated results for a six pole Chebyshev integrated non-uniform width ceramic waveguide filter and an integrated evanescent mode non-uniform width ceramic waveguide filter are presented in this paper showing improved spurious performance.